Wifi channel selection and subchannel selective transmissions

ABSTRACT

Systems, methods, and instrumentalities are provided to implement data transmission, comprising: receiving a first signal from an access point (AP) indicating that a primary channel is associated with a first frequency band associated with a first period of time; determining by an IEEE 802.11 station (STA) that a channel condition associated with a secondary channel is better than a channel condition associated with the primary channel; reserving the primary channel associated with the first frequency, wherein the reserving of the primary channel comprises occupying or reserving the primary channel during the first period of time; and sending data over the secondary channel while the primary channel is occupied or reserved.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/831,988, filed Jun. 6, 2013, the disclosure of whichis hereby incorporated by reference in its entirety.

BACKGROUND

Wireless networks (e.g., IEEE 802.11ac based networks) may provideaccess points (APs) for one or more stations (STAs) in a basic serviceset (BSS) with one or more operating channels. An AP may indicate thatone or more channels may be used for operation. A channel selected bythe AP may not be the channel that should be used for at least some ofthe STAs (e.g., it may not be an optimal channel for one or more STAs).For example, a channel that may be optimal for one STA may not beoptimal for other STAs in the same BSS. And, for example, different setsof STA may be monitoring and attempting to access different channels andmay not be aware of the channel access attempts or ongoing transmissionsby other STAs in the same BSS.

SUMMARY OF THE INVENTION

Systems, methods, and instrumentalities are provided to implementsubchannel selective transmission. A first signal may be received by anIEEE 802.11 station (STA) from an access point (AP) indicating that aprimary channel is associated with a first frequency band associatedwith a first period of time. A determination that a channel conditionassociated with a secondary channel is better than a channel conditionassociated with the primary channel may be made. The primary channelassociated with the first frequency may be reserved, wherein thereserving of the primary channel comprises occupying or reserving theprimary channel during the first period of time. Data may be sent overthe secondary channel while the primary channel is occupied or reserved.

A subchannel selective transmission (SST) capability may be indicated byan AP, or a STA, or by both. The primary channel and/or access channelmay be implicitly or explicitly indicated. A STA and an AP may reservethe medium by setting a network allocation vector (NAV) on one channel,or on multiple channels. An AP may specify intervals for transmissions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts an exemplary communications system.

FIG. 1B depicts an exemplary wireless transmit/receive unit (WTRU).

FIG. 1C depicts exemplary wireless local area network (WLAN) devices.

FIG. 2 depicts an exemplary WLAN system.

FIG. 3 depicts an example of channel alignment of an overlapping basestation subsystem (OBSS) in an IEEE 802.11ac network.

FIG. 4 depicts an exemplary format of a subchannel selectivetransmission (SST) element (e.g., as defined in IEEE 802.11ah).

FIG. 5 depicts an exemplary format for the channel activity schedulesubfield included in the SST element.

FIG. 6 depicts an example design of the primary and/or access channelindication information element (IE).

FIG. 7 depicts an example design of the channel activity schedulesubfield.

DETAILED DESCRIPTION

A detailed description of illustrative embodiments is described withreference to the various figures. Although this description provides adetailed example of possible implementations, it should be noted thatthe details are intended to be exemplary and in no way limit the scopeof the application. In addition, the figures may illustrate one or moremessage charts, which are meant to be exemplary (the messages may bevaried, reordered, or even omitted where appropriate).

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed features may be implemented. For example, awireless network (e.g., a wireless network comprising one or morecomponents of the communications system 100) may be configured such thatbearers that extend beyond the wireless network (e.g., beyond a walledgarden associated with the wireless network) may be assigned QoScharacteristics.

The communications system 100 may be a multiple access system thatprovides content, such as voice, data, video, messaging, broadcast,etc., to multiple wireless users. The communications system 100 mayenable multiple wireless users to access such content through thesharing of system resources, including wireless bandwidth. For example,the communications systems 100 may employ one or more channel accessmethods, such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include at leastone wireless transmit/receive unit (WTRU), such as a plurality of WTRUs,for instance WTRUs 102 a, 102 b, 102 c, and 102 d, a radio accessnetwork (RAN) 104, a core network 106, a public switched telephonenetwork (PSTN) 108, the Internet 110, and other networks 112, though itshould be appreciated that the disclosed embodiments contemplate anynumber of WTRUs, base stations, networks, and/or network elements. Eachof the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the networks 112. By way of example, the base stations 114 a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a HomeNode B, a Home eNode B, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it should be appreciated that thebase stations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it should be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B depicts an exemplary wireless transmit/receive unit, WTRU 102.WTRU 102 may be used in one or more of the communications systemsdescribed herein. As shown in FIG. 1B, the WTRU 102 may include aprocessor 118, a transceiver 120, a transmit/receive element 122, aspeaker/microphone 124, a keypad 126, a display/touchpad 128,non-removable memory 130, removable memory 132, a power source 134, aglobal positioning system (GPS) chipset 136, and other peripherals 138.It should be appreciated that the WTRU 102 may include anysub-combination of the foregoing elements while remaining consistentwith an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it should be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It should be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It should be appreciated that the WTRU 102may acquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C depicts exemplary WLAN devices, one or more of which may be usedto implement one or more of the features described herein, operating ina WLAN system 200. The WLAN system 200 may be configured to implementone or more protocols of the IEEE 802.11 communication standard, whichmay include a channel access scheme, such as DSSS, OFDM, OFDMA, etc. AWLAN may operate in a mode, e.g., an infrastructure mode, an ad-hocmode, etc.

The WLAN system 200 may include, but is not limited to, an access point(AP) 202, a station (STA) 204, and STA 206. The STA 204 and STA 206 maybe associated with the AP 202. A WLAN operating in an infrastructuremode may comprise one or more APs communicating with one or moreassociated STAs. An AP and STA(s) associated with the AP may comprise abasic service set (BSS). For example, AP 202, STA 204, and STA 206 maycomprise BSS 210. An extended service set (ESS) may comprise one or moreAPs (with one or more BSSs) and STA(s) associated with the APs.

An AP may have access to, and/or interface to, a distribution system(DS), which may be wired and/or wireless and may carry traffic to and/orfrom the AP. Traffic to a STA in the WLAN originating from outside theWLAN may be received at an AP in the WLAN, which may send the traffic tothe STA in the WLAN. Traffic originating from a STA in the WLAN to adestination outside the WLAN may be sent to an AP in the WLAN, which maysend the traffic to the destination.

As depicted, the AP 202 is in communication with a network 220. Thenetwork 220 is in communication with a server 230. Traffic between STAswithin the WLAN may be sent through one or more APs. For example, asource STA (e.g., STA 206) may have traffic intended for a destinationSTA (e.g., STA 204). STA 206 may send the traffic to AP 202, and, AP 202may send the traffic to STA 204.

A WLAN may operate in an ad-hoc mode. The ad-hoc mode WLAN may bereferred to as independent BSS. In an ad-hoc mode WLAN, the STAs maycommunicate directly with each other (e.g., STA 204 may communicate withSTA 206 without such communication being routed through an AP).

IEEE 802.11 devices (e.g., IEEE 802.11 APs in a BSS) may use beaconframes to announce the existence of a WLAN network. An AP, such as AP202, may transmit a beacon on a channel, e.g., a fixed channel, such asa primary channel. A STA may use a channel, such as the primary channel,to establish a connection with an AP.

STA(s) and/or AP(s) may use a Carrier Sense Multiple Access withCollision Avoidance (CSMA/CA) channel access mechanism. In CSMA/CA, aSTA and/or an AP may sense the primary channel. For example, if a STAhas data to send, the STA may sense the primary channel. If the primarychannel is detected to be busy, the STA may back off. For example, aWLAN or portion thereof may be configured so that one STA may transmitat a given time, e.g., in a given BSS. Channel access may include RTSand/or CTS signaling. For example, an exchange of a request to send(RTS) frame may be transmitted by a sending device and a clear to send(CTS) frame that may be sent by a receiving device. For example, if anAP has data to send to a STA, the AP may send an RTS frame to the STA.If the STA is ready to receive data, the STA may respond with a CTSframe. The CTS frame may include a time value that may alert other STAsto hold off from accessing the medium while the AP initiating the RTSmay transmit its data. On receiving the CTS frame from the STA, the APmay send the data to the STA.

A device may reserve spectrum via a network allocation vector (NAV)field. For example, in an IEEE 802.11 frame, the NAV field may be usedto reserve a channel for a time period. A STA that wants to transmitdata may set the NAV to the time for which it may expect to use thechannel. When a STA sets the NAV, the NAV may be set for an associatedWLAN or subset thereof (e.g., a BSS). Other STAs may count down the NAVto zero. When the counter reaches a value of zero, the NAV functionalitymay indicate to the other STA that the channel is now available.

The devices in a WLAN, such as an AP or STA, may include one or more ofthe following: a processor, a memory, a radio receiver, and/ortransmitter (e.g., which may be combined in a transceiver), one or moreantennas, etc. A processor function may comprise one or more processors.For example, the processor may comprise one or more of: a generalpurpose processor, a special purpose processor (e.g., a basebandprocessor, a MAC processor, etc.), a digital signal processor (DSP),Application Specific Integrated Circuits (ASICs), Field ProgrammableGate Array (FPGAs) circuits, any other type of integrated circuit (IC),a state machine, and the like. The one or more processors may beintegrated or not integrated with each other. The processor (e.g., theone or more processors or a subset thereof) may be integrated with oneor more other functions (e.g., other functions such as memory). Theprocessor may perform signal coding, data processing, power control,input/output processing, modulation, demodulation, and/or any otherfunctionality that may enable the device to operate in a wirelessenvironment, such as the WLAN of FIG. 2. The processor may be configuredto execute processor executable code (e.g., instructions) including, forexample, software and/or firmware instructions. For example, theprocesser may be configured to execute computer readable instructionsincluded on one or more of the processor (e.g., a chipset that includesmemory and a processor) or memory. Execution of the instructions maycause the device to perform one or more of the functions describedherein.

A device may include one or more antennas. The device may employmultiple input multiple output (MIMO) techniques. The one or moreantennas may receive a radio signal. The processor may receive the radiosignal, e.g., via the one or more antennas. The one or more antennas maytransmit a radio signal (e.g., based on a signal sent from theprocessor).

The device may have a memory that may include one or more devices forstoring programming and/or data, such as processor executable code orinstructions (e.g., software, firmware, etc.), electronic data,databases, or other digital information. The memory may include one ormore memory units. One or more memory units may be integrated with oneor more other functions (e.g., other functions included in the device,such as the processor). The memory may include a read-only memory (ROM)(e.g., erasable programmable read only memory (EPROM), electricallyerasable programmable read only memory (EEPROM), etc.), random accessmemory (RAM), magnetic disk storage media, optical storage media, flashmemory devices, and/or other non-transitory computer-readable media forstoring information. The memory may be coupled to the processer. Theprocesser may communicate with one or more entities of memory, e.g., viaa system bus, directly, etc.

Turning to FIG. 2, a WLAN in infrastructure basic service set (BSS) modemay have an access point (AP) for the basic service set and one or morestations (STAs) associated with the AP. The AP may have access orinterface to a distribution system (DS) or another type ofwired/wireless network that may carry traffic in and out of the BSS.Traffic to STAs may originate from outside the BSS, may arrive throughthe AP and may be delivered to the STAs. The traffic originating fromSTAs to destinations outside the BSS may be sent to the AP to bedelivered to the respective destinations. Traffic between STAs withinthe BSS may be sent through the AP where the source STA may sendstraffic to the AP and the AP may deliver the traffic to the destinationSTA. The traffic between STAs within a BSS may be peer-to-peer traffic.Such peer-to-peer traffic may be sent directly between the source anddestination STAs, e.g., with a direct link setup (DLS) using an IEEE802.11e DLS or an IEEE 802.11z tunneled DLS (TDLS). A WLAN using anindependent BSS mode may have no APs, and the STAs may communicatedirectly with each other. This mode of communication may be an ad-hocmode.

Using the IEEE 802.11 infrastructure mode of operation, the AP maytransmit a beacon on a fixed channel, usually the primary channel. Thischannel may be 20 MHz wide, and may be the operating channel of the BSS.This channel may also be used by the STAs to establish a connection withthe AP. The channel access in an IEEE 802.11 system may be Carrier SenseMultiple Access with Collision Avoidance (CSMA/CA). In this mode ofoperation, the STAs, including the AP, may sense the primary channel. Ifthe channel is detected to be busy, the STA may back off. One STA maytransmit at any given time in a given BSS.

In IEEE 802.11ac, very high throughput (VHT) STAs may support, e.g., 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels. The 40 MHz, and 80MHz channels may be formed, e.g., by combining contiguous 20 MHzchannels. A160 MHz channel may be formed, for example, by combiningeight contiguous 20 MHz channels, or by combining two non-contiguous 80MHz channels (e.g., referred to as an 80+80 configuration). For the80+80 configuration, the data, after channel encoding, may be passedthrough a segment parser that may divide it into two streams. Inversefast Fourier transform (IFFT), and time domain, processing may be doneon each stream separately. The streams may be mapped on to the twochannels, and the data may be transmitted. At the receiver, thismechanism may be reversed, and the combined data may be sent to the MAC.

FIG. 3 depicts an example of channel assignment of an overlapping basestation subsystem (OBSS) in an IEEE 802.11ac network. The IEEE 802.11acmay provide rules on channel selection for OBSS. For example, if an APor a mesh STA starts a VHT BSS that occupies one or more channels of anexisting BSS, the AP may select a primary channel of the VHT BSS thatmay be identical to the primary channel of one of the existing BSSs. Ifan AP or a mesh STA chooses to select a primary channel of a VHT BSSwith a 40 MHz, 80 MHz, 160 MHz, or 80+80 MHz operating channel widthfrom among the channels on which no beacons are detected during the OBSSscans, the selected primary channel may not be identical to thesecondary 20 MHz channel of any existing BSSs with a 40 MHz, 80 MHz, 160MHz or 80+80 MHz operating channel width. The primary channel may not beoverlapped with the secondary 40 MHz channel of an existing BSS with a160 MHz or 80+80 MHz operating channel bandwidth.

An AP or mesh STA may not start a VHT BSS with a 20 MHz operatingchannel width on a channel that may be secondary 20 MHz channel of anexisting BSS with a 40 MHz, 80 MHz, 160 MHz or 80+80 MHz operatingchannel width or may be overlapped with the secondary 40 MHz channel ofany existing BSSs with a 160 MHz or 80+80 MHz operating channel width.An AP or a mesh STA operating a VHT BSS with a 40 MHz, 80 MHz, 160 MHzor 80+80 MHz operating channel width, on detecting an OBSS whose primarychannel is the AP's or the mesh STA's secondary 20 MHz channel, mayswitch to 20 MHz BSS operation and/or may move to a different channel. Aprimary, and/or secondary channel may occupy a bandwidth other than thatspecified above. For example, the primary and secondary channels mayoccupy 5 MHz, instead of 20 MHz.

One or more spectra may be allocated in various countries around theworld for wireless communication systems such as WLANs. Such spectra maybe limited in the size and bandwidth of the channels they comprise. Thespectra may be fragmented. The available channels may not be adjacentand may not be combined for larger bandwidth transmissions, for example,in spectra allocated below 1 GHz in various countries. WLAN systems, forexample built on the IEEE 802.11 standard, may be designed to operate insuch spectra. The WLAN systems may be limited to smaller bandwidthsand/or lower data rates, compared to HT/VHT WLAN systems, for example,based on the 802.11n/802.11ac Standards.

IEEE 802.11ah may support sub 1 GHz modes of operation. The IEEE802.11ah may support OFDM physical layer (PHY) that may operate at below1 GHz. Such 802.11ah systems may operate in license-exempt bandsexcluding the TV White Space (TVWS). IEEE 802.11 may supportenhancements to MAC layer to support the enhance PHY layer whilecoexisting with other systems (e.g., 802.15.4, 802.15.4g, etc.). IEEE802.11ah may support Meter Type Control (MTC) devices in a macrocoverage area. The MTC devices (e.g., sensors, meters, etc.) may havecapabilities including, for example, support for extended range Wi-Fifor cellular offloading.

The spectrum allocation in one or more countries may be limited. Forexample, in China the 470-566 and 614-787 MHz bands may allow 1 MHzbandwidth. There may be a need to support 1 MHz only option in additionto a support for a 2 MHz with 1 MHz mode. The 802.11ah PHY may supportone or more of 1, 2, 4, 8, or 16 MHz bandwidths.

The 802.11ah PHY may operate at below 1 GHz and may be based on the802.11ac PHY. To accommodate the narrow bandwidths as needed by802.11ah, the 802.11ac PHY may be down-clocked by a factor of 10.Support for 2, 4, 8, and 16 MHz may be achieved by 1/10 down-clockingdescribed herein. Support for the 1 MHz bandwidth may need a PHYdefinition, e.g., with a Fast Fourier Transform (FFT) size of 32.

As described herein, IEEE 802.11ah may provide support for meters andsensors. For example, 1 to 6000 STAs may be supported within a BSS. Thedevices such as smart meters and sensors may have different requirementspertaining to the supported uplink and downlink traffic. For example,sensors and meters may be configured to periodically upload data to aserver, e.g., via uplink traffic. Sensors and meters may be queried orconfigured by a server. When the server queries or configures a sensorand/or a meter, the server may expect that the queried data to arrivewithin a setup interval. The server and/or application may expect aconfirmation for a configuration performed within a certain interval.The type of traffic patterns with networks having sensors and/or metersmay be different than the traffic patterns assumed for the usual WLANsystems.

In the 802.11ah the SIG field of the PLCP preamble of a packet, e.g.,one or more (e.g., 2) bits may be used to indicate the type ofacknowledgment expected as a response (e.g., Early ACK Indication) tothe packet: ACK (e.g., 00 value), BA (e.g., 01 value) and No ACK (e.g.,10 value). A value (e.g., 11 value) may be reserved for future use.

IEEE 802.11ah may provide support for Frequency Selective Transmission.

Frequency selective transmissions may allow narrow band transmission ina wideband of frequencies to allow better channel quality and highertransmission data rates. IEEE 802.11ah may allow an AP to transmit oneor more beacons per target beacon transmit time (TBTT) on one or moresub channels of the BSS. IEEE 802.11ah may include a submissionpermission bitmap in a beacon, which may identify the sub channels, theassociated STAs may use to transmit.

IEEE 802.11ah may provide support for channel indication in restrictedaccess window (RAW) and/or TWT fields. An AP may detect and/or receiveone or more packets on one of the channels it may indicate in itsbeacon. The AP may be able to support one channel (e.g., a primarychannel) or multiple channels within a BSS BW. AP may not be able todetect and/or decode parallel transmissions on different channels.

IEEE 802.11ah may provide support for a subchannel selectivetransmission element. FIG. 4 depicts an example format of subchannelselective transmission element. FIG. 5 depicts an example of a channelactivity schedule subfield that may be included in the SST element. Asdepicted in FIG. 4, the channel activity schedule may include thefollowing fields: channel activity bitmap, uplink activity bit, downlinkactivity bit, maximum transmission width, activity start time, etc.

The Channel Activity Bitmap subfield may include a bitmap indicating thechannels on which transmission activity may be expected or permitted.Each bit in the bitmap may correspond to one minimum width channel forthe band of operation. The least significant (LS) bit may correspond tothe lowest numbered operating channel of the BSS. A value (e.g., a valueof 1) in a bit position in the bitmap may mean that the AP may expectactivity or permit transmissions with bandwidth less than or equal toMaximum Transmission Width. The value 1 in a bit position may furthermean that the AP may include the channel, after the time indicated inthe Activity Start Time subfield. One or more bits in the bitmap may beset to a value 1.

The UL activity bit may indicate whether STAs associated with the APthat transmit the subfield may be permitted to transmit on thechannel(s) identified by the Channel Activity Bitmap and MaximumTransmission Width at the time indicated in the Activity Start Timesubfield. The DL Activity bit may indicate whether the AP that transmitsthe subfield may intend to transmit on the channel(s) identified by theChannel Activity Bitmap and Maximum Transmission Width at the timeindicated in the Activity Start Time subfield. The Maximum TransmissionWidth field may indicate the maximum permitted PPDU bandwidth for atransmission on the indicated channel.

The Activity Start Time subfield may include a value that may provide astart time for when the AP may expect activity on the channel(s)indicated in the corresponding Channel Activity Bitmap. The start timemay be equal to the next time, starting from the transmission of theframe containing the subfield, when the 20 least significant bits of theTSF for the BSS may match the value in the Activity Start Time subfield.

In a wireless network based on IEEE 802.11 (e.g., 802.11ah), the STAsmay have different channel operating modes. An AP may indicate that oneor more channels may be used for operation in its BSS for some period oftime. Due to the narrow bandwidth and frequency selectivity, the primarychannel of a BSS may not be the optimal (or the most preferred) channelfor some STAs to transmit or receive. The best channel(s) for some STAsmay not be the best channels for other STAs. One or more sets of STA maybe monitoring and attempting to access different channels. A method forSTAs and APs to conduct correct and efficient frequency selectivetransmission may be needed.

Frequency selective transmission may be provided. When an AP indicatesthat one or more channels may be used for its BSS' operation for someperiod of time, the STAs may select the best channels to conduct itsoperation, such as sending UL traffic to the AP. In order to have eachof the STAs and the AP to conduct correct and efficient frequencyselective transmissions various implementations may be provided.

Subchannel selective transmission capability indication(s) may beprovided. A STA and/or an AP may indicate that they support subchannelselective transmission (SST) capabilities. For example, the STA or theAP may include a SST indication of one or more bits in frames such as aprobe request and/or a probe response, a beacon, a short beacon, anassociation request and/or an association response, a re-associationrequest and/or a re-association response, or other control, management,and/or extension frames. Such a SST Indication may be part of a field,or subfield of a field, or an IE. For example, one or more of thefollowing elements may be used: the S1G Capabilities Element, S1GOperation Element, Very High Throughput (VHT) Capabilities Element, HEW(High Efficiency Wi-Fi) Capabilities Element, or VHSE (Very HighSpectral Efficiency) Capabilities Element that may be included in acontrol, management, and/or extension frames. The STAs and/or the APsmay exchange information indicating their support of SST duringassociation and/or at other times.

An AP may indicate that its BSS may operate using SST, e.g., byincluding a SST Operation Indication of one or more bit in frames suchas probe request and/or a probe response, a beacon, a short beacon, anassociation request and/or an association response, a re-associationrequest and/or a re-association response, or other control, management,and/or extension frames. Such an SST Operation Indication may be part ofa field, subfield of a field, or IE. For example, one or more of thefollowing elements may be used: the S1G Operation Element, VHT OperationElement, HEW Operation Element, or VHSE Operation Element that may beincluded in a control, management, and/or extension frames. An AP mayallow or reject a (re)association request from a STA based on whetherthe STA may support SST operations. For example, an AP may use aResultCode of Refused_SST_Not_Supported in the MLME-ReAssociate.Responseprimitive. The same ResultCode may be used for theMEME-(Re)Associate.Confirm primitive. In order to support these twoprevious primitives, SSTCapability may be included (e.g., may beincluded as a part of a different parameter, such as S1GCapabilitis) inthe MLME-(Re)Associate.Request and MLME-(Re)Associate.Indicationprimitives.

A Primary and/or Access Channel Indication may be explicitly provided.An access and/or primary channel may be a channel (e.g., of anybandwidth), which a STA may monitor and compete for access on the sameor a different channel(s) that may be available during a period, such asa SST period. An AP may indicate one or more dynamic primary and/oraccess channel(s) using a Primary/Access Channel Information Element,e.g., as depicted by example in FIG. 6.

As depicted in FIG. 6, the Primary/Access Channel Indication IE mayinclude the following fields: Element ID, Length, Number of Fields, etc.An Element ID may indicate that the current IE is a Primary/AccessChannel Assignment IE. The Length field may indicate the length of thePrimary/Access Channel Assignment IE. The Number of Fields may indicatethe number of Primary and/or Access Channel Reporting fields that may bein the current IE. If one Primary and/or Access Channel Reporting fieldis included by default, the Number of fields may be absent.

Each Primary and/or Access Channel Reporting field may include thefollowing subfields: Primary Channel(s), Access Channel(s), ChannelOperating Mode, Schedule, Group ID, SubGroup ID, Channel Assignment,Parameters, etc.

The Primary Channel(s) subfield may indicate the primary channel(s) fora BSS. If a primary channel schedule is included, the primary channel(s)may be dynamic and valid for the schedule included. The primarychannel(s) subfield may be indicated using a bitmap. For example, avalue of 1 may indicate a channel that may be a part of the primarychannel. In another example, the primary channel(s) subfield may beimplemented using a pair of subfields (e.g., channel number, channelbandwidth). In another example, if the Primary and/or Access ChannelIndication IE is used in conjunction with the SST element, the PrimaryChannel subfield may be implemented as an integer, which may indicate apositive position of the primary channel in the SST Channel Activitybitmaps. For example, if the Channel Activity bitmap in the SST Elementis 01111000, then an integer value of 3 in the Primary Channel subfieldmay indicate that the primary channel valid is the third positiveindication, which may correspond to channel 4. In anotherimplementation, an integer value (e.g., a value 3) in the PrimaryChannel subfield may indicate that the primary channel valid is thethird channel indicated (e.g., corresponding to channel 3).

The Access Channel(s) subfield may indicate the access channel(s) forthe BSS. If an access channel schedule is included, the accesschannel(s) may be valid for the schedule included. The access channel(s)subfield may be indicated using a bitmap. For example, a value 1 mayindicate a channel that may be a part of the access channel. In anotherexample, the access channel(s) subfield may be implemented using a pairof subfields (e.g., channel number, channel bandwidth). In anotherexample, if Primary/Access Channel Indication IE is used in conjunctionof the SST element, the Access Channel subfield may be implemented as aninteger, which may indicate the positive position of the access channelin the SST available channel(s) bitmaps. For example, if the availablechannels bitmap in the SST Element is 01111000, then an integer value of3 in the Access Channel subfield may indicate that the access channelvalid is the third positive indication, which may correspond to channel4. In another implementation, an integer value of 3 in the AccessChannel subfield may indicate that the access channel valid may be thethird channel indicated, which may correspond to channel 3.

The Channel Operating Mode subfield may be specified as described hereinusing, e.g., operating bandwidth, bandwidth contiguity, directionaltransmission, etc. The Channel Operating Mode(s) may be encoded by anumber referring to one or more particular Channel Operating Mode(s).The Channel Operating Mode(s) may be implemented as a bit map. Forexample, a positive indication 1 may indicate that the STA may becapable of a particular Channel Operating Mode.

The schedule subfield may include one or more of the followingschedules: Primary Channel Schedule, Access Channel Schedule, GroupSchedule, SubGroup Schedule, Sounding Schedule, or Preference IndicationSchedule.

A Primary Channel Schedule may be associated with the dynamic primarychannel and may specify when the primary channel(s) may be valid, whichmay be specified (e.g., using Start time, duration). The Start time maybe specified in TSF Timer values or using other time units and othertime references.

An Access Channel Schedule may be associated with the dynamic accesschannel and may specify when the access channel(s) may be valid, whichmay be specified (e.g., using Start time, duration). The Start time maybe specified in TSF Timer values or using other time units and othertime references.

The Group Schedule may provide a schedule for the group of STAs, such aswhen the STA may switch to conduct channel access using the indicatedprimary and/or access channel(s), when STA may awake to transmit and/orreceive, etc. The Group Schedule may provide the duration of theinterval assigned to a group of STAs.

The SubGroup Schedule may provide the schedule for the SubGroup of STAs,such as when the STA may switch to the conduct channel access using theindicated primary and/or access channel(s), or when the STA may wake upto transmit/receive. The SubGroup Schedule may comprise a Wakeup Offsetfrom the starting time of the Group Schedule, and/or the duration of theRAW/beacon subinterval/Access Window/TXOP assigned to the SubGroup.

The Sounding Schedule may provide the schedule during which theGroup/SubGroup STAs may wake up and monitor one or more of the channelsfor sounding frames from the AP.

The Preference Indication Schedule may provide a starting time andduration. The Preference Indication Schedule may provide aRAW/TWT/slots/beacon sub intervals during which a Group and/or SubGroupof STAs may be allowed to provide channel preference indication to theAP after conducting the sounding.

The Group ID of the Group of the STAs may access the channel,potentially using the indicated primary and/or access channel. The GroupID may be a default value that may refer to STAs that are not associatedwith the AP. The STAs may be grouped according to their capabilities,channel operation modes, transmit and receive capabilities, sectorizedoperation mode.

The SubGroup ID subfield may be the ID of a SubGroup of the STAs thatmay access the channel, potentially using the indicated primary and/oraccess channel. The SubGroup ID may be a default value that may refer toSTAs that are not associated with the AP. The STAs may be divided intosubgroups according to their capabilities, channel operation modes,transmit and receive capabilities, sectorized operation mode, etc.

The Channel Assignment subfield may indicate the channel assignmentprovided a STA, a Group or a SubGroup of STAs by the AP, which may beimplemented as bitmap, or the number of the starting channel, or thenumber of the channels (may be of the unit bandwidth) consisting of thetotal assigned channel to the STA, a Group or a SubGroup of STAs.

The Parameters subfield may provide the access parameters the STAs mayuse to access the channel for transmissions and/or providing channelfeedbacks, such as EDCA parameters, contention-based, contention-freeaccess, etc.

FIG. 7 depicts an example design of a Channel Activity Schedulesubfield. The Channel Activity Schedule subfield included in the SST maybe modified to indicate the location of the primary and/or accesschannel(s). A Primary and/or Access Channel Indication may beimplemented as a bitmap. A value 1 may indicate a channel that may be apart of the primary and/or access channel. The Primary and/or AccessChannel Indication may be implemented using a pair of subfields (e.g.,channel number, channel bandwidth). The Primary and/or Access ChannelIndication may be implemented as an integer, which may indicate thepositive position of the primary and/or access channel in ChannelActivity bitmap. For example, if the Channel Activity bitmap in the SSTElement is 01111000, then an integer value of 3 in the Primary and/orAccess Channel Indication may indicate that the primary and/or accesschannel that may be valid may be the third positive indication, whichmay correspond to channel 4. For example, an integer value of 3 in thePrimary and/or Access Channel Indication may indicate that the primaryand/or access channel valid may be the third channel indicated which maycorrespond to channel 3.

A subset of the subfields of the Primary and/or Access ChannelIndication IE may be implemented as a subfield or subsets of subfieldsof an IE. Such an IE may include, for example, the SST Element, theS1G/VHT/HEW/VHSE Operation Element, or as a part of any Action frames,Action without ACK frames, control, management, extension frames, suchas beacon, short beacon, Probe Response, Association Response, S1GAction frame or in MAC/PLCP headers.

An Implicit Primary and/or Access Channel Indication may be provided.The primary and/or access channel may be implicitly indicated by the APin frames such as beacon, short beacon, or in control, management orextension frames. Such implicit indication of primary and/or accesschannel may be included in a field, a subfield, or an IE, such as SSTElement, S1G Operation element, HEW Operation Element, VHSE OperationElement, etc. For example, if an SST Element or any other type ofElement indicates that one or more channels may be used for some periodof the time for SST, the primary and/or access channel may be implicitlyindicated to be the lowest or highest channel indicated in the SST.

If the AP has previously indicated a primary and/or access channel forits BSS, and if the available channels for some period of time indicatedin, e.g., the SST element, include the primary and/or access channel,then the primary and/or access channel may remain the same as previouslyindicated by the AP. If the available channels for some period of timeindicated in, e.g., the SST element, do not include the primary and/oraccess channel which the AP has previously indicated, then one or morechannel(s) at a default place may be considered as the primary channelor access channel. The primary and/or access channel may be the highestand lowest channel(s) indicated or the higher or lower part of a defaultchannel.

SST using implicit and/or explicit Primary and/or Access ChannelIndication may be provided. In explicit primary and/or access channelindication, an AP may include a Primary/Access Channel Indication IE, inconjunction with or instead of an SST Element or a modified SSTElement., The Primary/Access Channel Indication IE may be provided inframes such as beacon, short beacon, Probe Response, (Re)AssociationResponse, or other type of control, management, or extension frames, toindicate the location of the primary and/or access channels for its BSSfor some periods of time, which may be the beacon (sub)interval(s),RAWs, or TWTs following the beacon or short beacon.

In implicit primary and/or access channel indication, an AP mayimplicitly indicate the location of the Primary and/or Access channelsusing the locations or fields in one of its field or subfields (e.g.,the Channel Activity Bitmap in the SST element) in frames such asbeacon, short beacon, or other type of control, management, or extensionframes, to indicate the location of the primary and/or access channelsfor its BSS for some periods of time, which may be the beacon(sub)interval(s) following the beacon or short beacon.

A STA that is capable of SST and is allowed to access medium based on,for example, its RAW/TWT or other schedule assignment, or its (sub)group ID. The information may be indicated in a beacon or short beaconor a resource allocation frame, etc. Such a STA may determine thelocation of the primary and/or access channel based on the informationreceived from the AP.

The STA may monitor the primary channel and/or the access channel tocompete for medium access. Assuming that, for example, the best channelfor a STA is channel 1, and the primary and/or access channel is channel2, then in one example, the STA may monitor both Channel 1 and 2. If theSTA has gained access to both channels, it may transmit duplicateframes, such as duplicated RTS, or duplicated data on both channels 1and 2. The AP may then respond with duplicated frames, such asduplicated CTS or ACK, on both channel 1 and 2. The STA and the AP maycontinue their packet exchanges until their transmissions are completed.The STA and the AP may reserve the medium by setting the NAV on theprimary and/or access channel and then transmit their data packets/ACKson Channel 1, which is the best for the STA. The STA and the AP mayreserve the medium by setting the NAV on both the primary and/or accesschannels and the best channel for the STA/AP, e.g., channels 1 and 2,and transmit their data packets/ACKs on Channel 1.

Other STAs that attempt to access the medium to communicate with the APmay monitor Channel 2 and may transmit when they are able to reserve themedium or gain access on the primary and/or access channel. One or moreSTAs may transmit when they are able to reserve the medium or gainaccess on the primary and/or access channel and their best channels,e.g., the channels on which they intend to use for the main bulk oftheir transmissions by, e.g., a successful RTS/CTS exchange with the AP.

AP Driven Frequency Selective Transmissions may be provided. The SST maybe AP driven. An AP may specify intervals for DL transmissions. The STAsmay monitor the primary and/or access channel and/or the entireavailable channels indicated by the Channel Activity bitmap to receivepackets.

An AP may specify intervals for channel feedbacks for the STAs. One STAmay be assigned to each slot in the interval. Each of the STAs mayprovide their feedback on their best channel or on the primary and/oraccess channel indicated. The AP may provide a schedule through abeacon, short beacon, a resource allocation frame, etc., to provide aschedule and channel assignment for the STAs so that the STAs mayconduct UL and DL transmissions with the AP.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element may be used alone or in any combination with theother features and elements. Other than the 802.11 protocols describedherein, the features and elements described herein may be applicable toother wireless systems. Although the features and elements describedherein may have been described for uplink operation, the methods andprocedures may be applied to downlink operation. Although SIFS may havebeen used herein to indicate various inter frame spacing, other interframe spacing, e.g., RIFS or other agreed time interval may be applied.In addition, the methods described herein may be implemented in acomputer program, software, or firmware incorporated in acomputer-readable medium for execution by a computer or processor.Examples of computer-readable media include electronic signals(transmitted over wired or wireless connections) and computer-readablestorage media. Examples of computer-readable storage media include, butare not limited to, a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, optical media such as CD-ROM disks, and digital versatile disks(DVDs). A processor in association with software may be used toimplement a radio frequency transceiver for use in a WTRU, WTRU,terminal, base station, RNC, or any host computer.

1-21. (canceled)
 22. A first IEEE 802.11 device comprising: a processorconfigured to: associate with a second IEEE 802.11 device; receive atransmission from the second IEEE 802.11 device, wherein thetransmission includes an indication of a channel available for use bythe first IEEE 802.11 device for a period of time, and wherein thechannel is associated with a primary channel, and wherein the indicationis provided using a bitmap; and access the indicated channel during theperiod of time.
 23. The first IEEE 802.11 device of claim 22, whereinthe processor is further configured to receive an information element.24. The first IEEE 802.11 device of claim 23, wherein the bitmap iscarried in the received information element.
 25. The first IEEE 802.11device of claim 24, wherein the channel is indicated in the bitmap by alocation of a value of “1” in the bitmap.
 26. The first IEEE 802.11device of claim 22, wherein the channel is associated with a basicservice set that comprises the first IEEE 802.11 device and the secondIEEE 802.11 device.
 27. The first IEEE 802.11 device of claim 22,wherein the first IEEE 802.11 device is an IEEE 802.11 station.
 28. Thefirst IEEE 802.11 device of claim 23, wherein the information elementcomprises at least one of: a channel operating mode indication or aparameter for use by the first IEEE 802.11 device to access the channel.29. A method associated with a first IEEE 802.11 device, the methodcomprising: associating with a second IEEE 802.11 device; receiving atransmission from the second IEEE 802.11 device, wherein thetransmission includes an indication of a channel available for use bythe first IEEE 802.11 device for a period of time, and wherein thechannel is associated with a primary channel, and wherein the indicationis provided using a bitmap; and accessing the indicated channel duringthe period of time.
 30. The method of claim 29, further comprisingreceiving an information element.
 31. The method of claim 30, whereinthe bitmap is carried in the received information element.
 32. Themethod of claim 31, wherein the channel is indicated in the bitmap by alocation of a value of “1” in the bitmap.
 33. The method of claim 29,wherein the channel is associated with a basic service set thatcomprises the first IEEE 802.11 device and the second IEEE 802.11device.
 34. The method of claim 29, wherein the first IEEE 802.11 deviceis an IEEE 802.11 station.
 35. The method of claim 30, wherein theinformation element comprises at least one of: a channel operating modeindication or a parameter for use by the first IEEE 802.11 device toaccess the channel.